Commutator



P 1954 P. e. HANSEL ETAL 3,129,392

COMMUTATOR Filed Jan. 27, 1959 INVENTORS 4 a. #wsn Fave-210k 6'- ,P/c/WE? BYIV/ZZMM M Pox/z gnaw AT ORNEYS United States Patent 3,129,392 COMMUTATUR Paul G. Hansel, Greenvale, Frederick G. Richter, Great Neck, and William H. Paulstich, Merrick, N.Y., assignors to Siervo Corporation of America, New Hyde Park, N.Y., a corporation of New York Filed .lan. 27, 1959, Ser. No. 789,366 14 Claims. (Cl. 3337) This invention relates to a commutator of electrical energy, and more particularly to a commutator of radiofrequency energy useful in radio-navigation systems.

In radio-navigation systems, such as for example a quasi-Doppler directional system, a radio-frequency commutator or distributor is employed to apply energy from a transmitter in succession to a plurality of antennas, arranged in circular array. The function of the commutator is to cause the effective point of reception, or transmission, to travel around the circular array of uniformly spaced antenna elements at a substantially constant rate.

The commutator is one of the most critical elements in the system because the design determines the signal sensitivity, the bearing accuracy and the degree of spurious amplitude modulation imposed on the incoming or outgoing signal. Minimum amplitude modulation of the received or transmitted signal is produced if the coupling of the receiver or transmitter from one antenna to the next is varied in a substantially sinusoidal manner.

Accordingly, it is a primary object of this invention to provide a radio-frequency commutator which is capable of efficient, reliable performance and which is relatively small in size and amenable to mass production techniques.

It is a further object of the invention to provide a commutator which has a high switching ratio and switching element isolation.

It is a still further object of the invention to provide a commutator having smooth blending capabilities in switching from one antenna to the next, whereby data smoothing, filtering and unwanted amplitude modulation are minimized.

It is a feature of the invention to provide a commutator having low insertion loss over the entire frequency range of operation in a single antenna switching commutator.

It is another feature of the invention to provide a commutator having low acoustic noise.

In accordance with an aspect of the invention, there is provided a commutator for applying radio-frequency energy between a plurality of antennas and an electrical circuit. The commutator is characterized by a stator member of non-magnetic material, having a planar surface and including a plurality of magnetic transformer sections, one for each of the antennas. The transformer sections are positioned in a circular array, and each having a portion terminating flush with the planar surface. The transformer sections are scanned by a complementary transformer section positioned in a rotor member, also having a planar surface disposed contiguously with the planar surface of the stator member. The transformer section in the rotor is positioned so that when the rotor is rotated, it describes a circle coextensive with the circular array of transformer sections in the stator, whereby when one of the transformer sections in the respective members is energized, electromagnetic energy is transferred to the opposing transformer section.

In accordance with a more limited aspect of the invention, each of the magnetic transformer sections comprises a half-toroid, the respective ends of the half-toroids being flush with the planar surface.

The above-mentioned and other features and objects of this invention and the manner of attaining them will be- ICC come more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawing, which is an exploded, perspective view of the novel commutator, and includes a cut-away view of a half-toroid transformer section.

Referring now to the drawing, the commutator comprises a circular stator member 1, generally in the form of a non-magnetic plate of uniform thickness, having a planar surface 2. The stator is made of a material having a high dielectric constant and is preferably made by casting a suitable plastic, for example, an epoxy resin.

The antenna switching elements comprise a plurality of half-toroid transformer sections 3, two of which are shown in the cut-away portion of the drawing. If the stator is made of an epoxy resin, the half-toroid transformer sections 3 are cast into the body of the stator member 2. The half-toroidal sections 3 are arranged circularly in the stator, with the ends 4 thereof terminating flush with the planar surface of the stator. The ends of the half-toroidal sections are aligned radially, as suggested by the dotted line extending from the center of the stator through the opposite ends of one half-toroidal section. The half-toroidal sections are also disposed coaxially in the stator 1.

The material of the toroidal core is, of course, magnetic, such as a soft iron, but is preferably made of a soft ferrite, such as nickel-zinc or manganese-zinc ferrites.

Each of the half-toroidal transformer sections includes a winding 5 coupled to an antenna input terminal 6, there being one antenna input terminal for each antenna serviced by the commutator. As shown, the antenna input terminals are mounted on the periphery of the stator 1, and each in close proximity to the half-toroidal section to which it is coupled.

The plurality of magnetic transformer sections in the stator is scanned by a complementary transformer section in the form of a similar half-toroid 7 cast in a non-magnetic rotor member 8. The rotor 8 is of similar configuration to the stator 1, having a planar surface in contiguous and slightly spaced relation with the planar surface 2 of the stator. The spacing between the members may be of the order of .004 inch. The half-toroid 7 in the rotor is positioned so that its ends terminate flush with the planar surface and is radially displaced from the axis of the rotor, so as to describe a circle during the rotation of the rotor, which is coextensive with the circle defined by the half-toroidal sections in the stator.

To obtain smooth sinusoidal blending from one antenna to the next, the ends of toroidal core 7 are wider, or longer, in the direction of rotation, than the corresponding dimension of the ends 4. The overlap of the core '7 provides smooth transistion in scanning from one core 3 to the next.

The rotor 8 may be rotated by a motor 9, which is coupled in driving relation to the rotor over a shaft 10a.

Electromagnetic energy is applied to the antenna input, or received from the antenna input, by a circuit 10, shown as a transmitter or a receiver. Assuming the circuit 16 is a transmitter, the energy is applied to the antennas via leads 11 to a transformer comprising a primary 12, secondary 13, over leads 14 to the half-toroidal section 7, the opposing half-toroidal section 3 and to the associated antenna input 6.

The pirimary 12 and secondary 13 comprise cup-shaped cores having a centrally located post 15 on which the respective primary and secondary windings are mounted, the primary winding 16 being shown in the drawing. The leads 14 from the toroidal section 7 are connected to the secondary winding, which is not shown. The cupshaped cores also terminate flush with the planar surfaces and may be made of any suitable magnetic material, such as the ferrites mentioned above.

It is to be realized, of course, that other forms of magnetic cores may be employed in place of the half-toroidal sections. Similarly, other shapes of cores may be utilized in place of the cup-shaped cores illustrated. However, the illustrated embodiment has provided excellent results, particularly when soft ferrite material has been utilized for both the toroidal and cup-shaped cores.

Although a commutator for one array of antennas has been described and illustrated, it is obvious that additional radial rows of switching elements may be secured in the stator and scanned by an appropriately positioned transformer section in the rotor.

For simplicity, the stator and rotor members are shown without a protective housing; however, in practice an aluminum or brass housing has been found suitable for the plastic rotor and stator members.

While the foregoing description sets forth the principles of the invention in connection with a specific design, it is to be clearly understood that this description is made only by way of example and not as a limitation of the scope of the invention as set forth in the objects thereof and in the accompanying claims.

We claim:

1. A commutator for applying electrical energy successively between a plurality of antennas and an electrical circuit, comprising a stator member of non-magnetic material having a planar surface, a plurality of magnetic transformer sections, one for each of the antennas, secured in said stator member, the transformer sections being positioned in circular array and each having an end terminating flush with said planar surface, and means for scanning said transformer sections comprising a rotor member having a planar surface in contiguous relation to the planar surface of said stator member, and a complementary magnetic transformer section secured in said rotor member having an end terminating flush with the rotor planar surface.

2. The commutator according to claim 1, wherein said magnetic transformer sections comprise half-toroidal cores, a winding on each of the cores in said stator member and a complementary winding on the core in said rotor member, whereby said complementary windings constitute the primary and secondary toroidal transformer sections.

3. The commutator according to claim 1, and further comprising means for rotating said rotor member, a circuit for supplying energy to or receiving energy from the antennas, and means coupling said circuit to said magnetic transformer section in said rotor member.

4. The commutator according to claim 1, wherein said means for coupling the energy from said circuit to said rotor transformer section comprises a transformer having a pair of cores, one of said cores being mounted in said stator section, the other of said cores being mounted in said rotor section, the ends of said cores being co-exte'nsive and flush in the respective planar surfaces of said stator and rotor members.

5. A commutator for applying electrical energy successively between a plurality of antennas and an electrical circuit, comprising rotor and stator members, each having a planar surface of non-magnetic material and mounted so that the planar surfaces are oppositely disposed and in contiguous relationship, a magnetic transformer section mounted in said rotor member, relatively displaced from the center thereof and having an end occupying a relatively small area and terminating substantially flush with said planar surface thereof, a plurality of similarly shaped magnetic transformer sections mounted in said stator member and having ends radially displaced a similar distance from the center thereof and terminating substantially flush with said planar surface thereof, whereby the radius of the arc defined by the plurality of said magnetic transformer sections is equal to the radius of the arc described by said first-mentioned magnetic transformer section during the rotation of the rotor member, the section in said rotor member constituting one part of a magnetic circuit and the instantaneously opposed section in the stator circuit constituting a second part of the magnetic circuit, whereby electromagnetic energy may be transferred successively between the magnetic section in said rotor member and the plurality of sections in said stator member, separate antenna connections to the respective magnetic transformer sections of said stator member, and single connection means to the magnetic transformer section of said rotor member whereby said last-defined means may serve to sequentially scan all antenna connections in a cycle of rotor movement.

6. The commutator according to claim 5, wherein said magnetic transformer sections comprise half-toroid transformer sections, a winding on each of the half-toroid sections in said stator member and a winding on the half-toroid section in said rotor member, the windings constituting .the primary and secondary of a transformer.

7. A commutator of electrical energy, comprising ro :tary and stator members, each having a planar surface and mounted so that the planar surfaces are oppositely disposed and in contiguous relationship, a half-toroid magnetic transformer section mounted in said rotary member, relatively displaced from the center thereof and occupying a relatively small area of said planar surface, a plurality of similarly shaped half-toroid magnetic transformer sections mounted in said stator member and radially displaced a similar distance from the center thereof whereby the radius of the arc defined by the plurality of said magnetic transformer sections is equal to the radius of the are described by said first-mentioned magnetic transformer section during the rotation of the rotary member, windings on each of the halfatoroid sectious on said rotary and stator members, the windings for any given pair of instantaneously opposed half-toroid sections constituting the primary and the secondary of a transformer, the section in said roltary member constituting one part of a magnetic circuit, and the instantaneously opposed section in the stator circuit constituting a sec- 0nd part of the magnetic circuit, whereby electromagnetic energy may be transferred successively between the magnetic section in said rotary member and the plurality of sections in said stator member; and a plurality of antenna input terminals mounted on the periphery of said stator member, the windings on said half-toroid sections in said stator member being coupled respectively to said antenna input terminals, an electric circuit for transmitting energy to or receiving energy from said antenna input terminals, and means for transferring said energy from the transformer section of said rotary member to said electric circuit. 7

8. The commutator according to claim 7, wherein said means for transferring energy comprises a transformer having two similarly shaped cores mounted respectively in said stator and rotary members, the ends of the respective cores terminating flush with said respeotive planar surfaces, a winding on the core mounted in said stator member and coupled to said electric circuit, and a winding on the other of said cores coupled to said half-toroid magnetic section in said rotary member.

9. A commutator for applying radio frequency energy to a plurality of antennas, comprising a nonmagnetic circular stator member having a planar surface, a plurality of half-toroid transformer sections hired in said stator section with the ends of the half-tortoids 'flush with said planar surface, said half-toroid sections being arranged in a circle and coaxial with the'center of said stator, the ends of each section being positioned on a radius of the circle, a plurality of antenna input terminals mounted on the periphery .of said stator member, one for each half-toroid section, a winding of each section being coupled to an associated antenna input terminal; a circular rotor member of non-magnetic material having a planar surface and positioned so that the planar surface of said stator and rotor members are in contiguous relation, a complementary half-toroid transformer section fixed in said rotor member with the ends of the half-toroid section flush with said planar surface, said half-toroid being radially aligned and positioned to describe a circle during the rotation of said rotor, coextensive with the circle defined by the sections in said stator, means for rotating said rotor, whereby each of the sections in said stator is successively scanned by the section in said rotor for transferring electromagnetic energy therebetween.

10. The commutator according to claim 9, and further comprising a second pair of complementary transformer sections in said rotor and stator respectively, means coupling the transformer section in said rotor to the halftoroid section in said rotor, and means coupling said transformer section in said stator to an electrical circuit, whereby the electrical circuit is coupled successively to said antenna over said second pair of transformer sections, said half-toroid in said rotor, and successive ones of said half-toroids in said stator to said antenna input terminals.

11. The commutator according to claim 10, wherein each of said second transformer sections comprises a cupshaped core having a centrally located post, and a winding positioned on said post.

12. The commutator according to claim 9, wherein said half-toroid sections comprise ferrite cores.

13. The commutator according to claim 11, wherein each of said cup-shaped cores comprises ferrite material.

14. The commutator according to claim 9, wherein the effective angular width of the ends of said half-toroid section in said rotor member is wider than the ends of the cores in said stator member, whereby blending of commutation from one antenna to the next is obtained.

References Cited in the file of this patent UNITED STATES PATENTS 1,813,913 Clokey July 14, 1931 2,098,002 Guerin Nov. 2, 1937 2,275,974 Mathes Mar. 10, 1942 2,422,601 Tashjian June 17, 1947 2,879,483 Montani Mar. 24, 1959 

1. A COMMUTATOR FOR APPLYING ELECTRICAL ENERGY SUCCESSIVELY BETWEEN A PLURALITY OF ANTENNAS AND AN ELECTRICAL CIRCUIT, COMPRISING A STATOR MEMBER OF NON-MAGNETIC MATERIAL HAVING A PLANAR SURFACE, A PLURALITY OF MAGNETIC TRANSFORMER SECTIONS, ONE FOR EACH OF THE ANTENNAS, SECURED IN SAID STATOR MEMBER, THE TRANSFORMER SECTIONS BEING POSITIONED IN CIRCULAR ARRAY AND EACH HAVING AN END TERMINATING FLUSH WITH SAID PLANAR SURFACE, AND MEANS FOR SCANNING SAID TRANSFORMER SECTIONS COMPRISING A ROTOR MEMBER HAVING A PLANAR SURFACE IN CONTIGUOUS RELATION TO THE PLANAR SURFACE OF SAID STATOR MEMBER, AND A COUPLEMENTARY MAGNETIC TRANSFORMER SECTION SECURED IN SAID ROTOR MEMBER HAVING AN END TERMINATING FLUSH WITH THE ROTOR PLANAR SURFACE. 